This is important for people with problems, related to this addon.

You will get a task to complete
Your task is: copy the path of the vehicle model.

Concrete example:
1: Open Spawnmenu, where you open for example: vehicles, but go to spawnlists
2: Click on the "+" next to "Browse" or for people who have their game in another language, next to the gearwheel
3: Click on the "+" next to the "Addons" folder
4: Click on the text "Roy's Cars - Ford"
5: Right-Click on the 1969 mustang prop thumbnail and click on the "Copy to clipboard" button.

My result: "models/royscars/ford_mustang_302.mdl"